What is the best food here according to health?

There are a lot of dishes made with olive oil. You can try the appettizers (meze) at any restaurant. Here is a good list here.

Also, people love the Turkish breakfast all around the world, since it is just a little bit of everything. It's light and healthy food, that you can constantly eat.. http://www.turkeytravelplanner.com/details/Food/TkBreakfast.html